The present invention relates to providing access to redundant pathways connected to a plurality of data storage devices. There are many well-known methods in the prior art for effecting such redundant access. For example, a fibre channel arbitrated loop has been designed for use on two communication loops connected to a plurality of data storage devices. Each loop is typically independently controlled, and in systems offering high-availability of the storage devices, the system may compensate for failed components. There are many different solutions in the prior art for allowing such high-availability, but these solutions have focused upon having redundant disks, so that a disk may be hot-swapped if it fails, as well as redundant controller cards, processors, power supplies, fans, etc. that may be hot-swapped with a new unit if the old one fails. These solutions do not address the problem of a communication path that fails, while the controlling hardware remains intact. Such a problem may occur if the physical cable connection is pulled loose, breaking one of the fibre loops in a dual-loop fibre channel system. One conventional solution is to require that a secondary data storage controller handle the input/output processing of data requests through a redundant path to replace the primary controller attached to the now-defunct communication path.
Information relating to the fiber-channel architecture may be found in American National Standards Institute (ANSI) standard X3.232-1994 promulgated by ANSI Committee X3T9.3 on Fibre Channel. This reference is incorporated herein by reference.